Optimize Your SQL by Reformulating the Spec

As SQL developers, we tend to think of performance tuning in terms of crafting the best table indices, avoiding scalar and table valued functions, and analyzing query plans (among other things). But sometimes going back to the spec and applying some properties of elementary math can be the best way to begin to improve performance of SQL queries which implement mathematical formulas. This article is a case study of how I used this technique to optimize my SQL implementation of the Inverse Simpson Index.

Cube v rollup

Round averages

Not Again!

NULL Aggregates

Script to get max dates on tables that contain a certain column.

This script will allow you to get maximum date associated with tables that contain a certain column.

SUM and Addition of Null

Cumulative Aggregates in SQL Server Reporting Services

In this tip, we will see how to build a report which shows the cumulative sales amount for the current month, current quarter (QTD) and current year (YTD) in a single crosstab (tablix) report, which makes it easy to compare the data.

Script to calculate the Median value for SQL Server data

The standard SQL language has a number of aggregate functions like: SUM, MIN, MAX, AVG, but a common statistics function that SQL Server does not have is a built-in aggregate function for median. The median is the value that falls in the middle of a sorted resultset with equal parts that are smaller and equal parts that are greater. Since there is no built-in implementation for the median, the following is a simple solution I put together to find the median.

Grouping Sets